diff --git a/xt/cpp_comments.t b/xt/cpp_comments.t
index 8558de0..658a110 100644
--- a/xt/cpp_comments.t
+++ b/xt/cpp_comments.t
@@ -7,7 +7,6 @@ BEGIN {
 }
 
 use Test::More;
-use t::lib::Test;
 
 my @c_files = (<*.c>, <*.h>, <*.xs>);
 plan tests => scalar(@c_files);
@@ -25,7 +24,7 @@ foreach my $file (@c_files) {
         $line++;
         if (/^(.*)\/\//) {
             my $m = $1;
-            if ($m !~ /\*/ && $m !~ /http:$/ && $m !~ m!"/*?$!) { # skip the // in c++ comment in parse.c
+            if ($m !~ /\*/ && $m !~ /(?:file|http|ftp):$/ && $m !~ m!"/*?$!) { # skip the // in c++ comment in parse.c
                 fail("C++ comment in $file line $line: $m");
                 next FILE;
             }